Coolants employed in power generating systems aboard spacecraft normally circulate at elevated temperatures which require cooling by a radiator. This is typically done by employing heat pipe radiators which transfer the excessive heat to outer space. Conventional heat pipes usually employ a two-phase working fluid which absorbs coolant heat in an evaporator section where the working fluid becomes vaporized. The vaporized fluid flows over radiator fins which radiate heat to outer space and cause condensing of the working fluid which is then recirculated as liquid back to the evaporator section.
The radiator fins are normally mounted to the exterior of a spacecraft where they become vulnerable to laser weapons which can be trained on the radiator causing ordinary aluminum metal fins to melt. Less powerful laser impingement could prevent the condenser section of the radiator from condensing the vaporized working fluid therein so that the two-phase exchange of the working fluid cannot be completed. This would result in the inability of the radiator to achieve heat transfer between the coolant and the radiator. As an end result the coolant would remain at an overly high temperature thereby ultimately causing failure of the spacecraft power plant.